不同活力花生种子的扫描电镜观察和能谱分析

Studies on Different Vigor of Peanut Seeds with S. E. M. and E. D. S.

花生种子经人工老化处理后活力明显下降,用25％PEG处理可提高种子活力,从扫描电镜观察看到,高活力种子胚根表皮细胞完整,老化处理后,表皮细胞呈疏松突起,严重的成块状脱落,皮层裸露,出现畸形很尖,能谱分析表明,高活力种子胚根尖细胞内含有多种元素,其含量的百分比顺序为:K>Ca>Si>P>S>Al>Cl。根尖含Ca最多,越往上部逐渐减少;K的含量却相反,根尖最低,越往上部越高,人工处理的种子Ca含量明显下降,老化10天以上的种子,胚根尖细胞的Ca完全消失,K的含量也随老化时间的增加而减少,PEG渗调处理能明显增加Ca的含量,减少细胞劣变的损伤,防止表皮细胞的脱落,因而提高种子活力。

When peanut seeds were accelerated aging in 90% relative humidity and 35℃ temperature for 5-25 days, the germination percentage and vigor index decreased. Osmoconditioning of peanut seeds with 25% PEG, the germination percentage and vigor index were increased. Studies with E. D. S. （Energy Dispersion Scanner） indicated that many mineral elements were located in microregion of radicle cells in high vigor seeds. The Sequence of percentage of mineral elements is: K>Ca>Si>P>S>Al>Cl. Ca2+ content in root tip was the highest and K+ in that was the lowest. After accelerated aging, Ca2+ content was greatly declined, or disappeared, and K+ was descended also. Studies with S. E. M. （Scanning Electric Microscope） indicated that the epidermal cells of radicle in high vigor seeds were in good condition （integrated）. After accelerated aging, the appearance of epidermal cells became loosely and protrudingly. If seeds were deteriorated seriously, the epidermis was falling down piece by piece, and the cortical cells were exposed. The root tip was deformed also. Osmoconditioning of the seeds with PEG, Ca2+ content was markedly increased. The damage on epidermal cells was partially repaired and the epidermis was almost integrated. Project supported by the National Natural Science Foundation of China.